package world

import (
	"testing"

	"github.com/stretchr/testify/require"
)

func TestCircles_WrapCopies_AppearInsideViewportWhenViewportEqualsWorld(t *testing.T) {
	t.Parallel()

	// World 10x10 units => 10px at zoom=1 when viewport==world.
	w := NewWorld(10, 10)
	w.SetCircleRadiusScaleFp(SCALE)
	w.resetGrid(2 * SCALE)

	type tc struct {
		name        string
		x, y        float64
		r           float64
		wantCenters [][2]float64 // expected (cx,cy) in canvas px for zoom=1, worldRect min = 0
	}

	// Camera is centered => expanded world rect equals [0..W)x[0..H) when margin=0.
	params := RenderParams{
		ViewportWidthPx:  10,
		ViewportHeightPx: 10,
		MarginXPx:        0,
		MarginYPx:        0,
		CameraXWorldFp:   5 * SCALE,
		CameraYWorldFp:   5 * SCALE,
		CameraZoom:       1.0,
	}

	tests := []tc{
		{
			name: "bottom boundary wraps to top",
			x:    5, y: 9, r: 2,
			// Centers: original at y=9, copy at y=-1.
			wantCenters: [][2]float64{{5, 9}, {5, -1}},
		},
		{
			name: "right boundary wraps to left",
			x:    9, y: 5, r: 2,
			wantCenters: [][2]float64{{9, 5}, {-1, 5}},
		},
		{
			name: "corner wraps to three extra copies",
			x:    9, y: 9, r: 2,
			wantCenters: [][2]float64{{9, 9}, {-1, 9}, {9, -1}, {-1, -1}},
		},
		{
			name: "no wrap inside",
			x:    5, y: 5, r: 2,
			wantCenters: [][2]float64{{5, 5}},
		},
	}

	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			w2 := NewWorld(10, 10)
			w2.resetGrid(2 * SCALE)

			_, err := w2.AddCircle(tt.x, tt.y, tt.r)
			require.NoError(t, err)

			for _, obj := range w2.objects {
				w2.indexObject(obj)
			}

			plan, err := w2.buildRenderPlanStageA(params)
			require.NoError(t, err)

			d := &fakePrimitiveDrawer{}
			drawCirclesFromPlan(d, plan, w2.W, w2.H, true, w.circleRadiusScaleFp)

			cmds := d.CommandsByName("AddCircle")
			require.Len(t, cmds, len(tt.wantCenters))

			// Collect centers (ignore radius for this test).
			got := make([][2]float64, 0, len(cmds))
			for _, c := range cmds {
				require.Len(t, c.Args, 3)
				got = append(got, [2]float64{c.Args[0], c.Args[1]})
			}

			// Order is deterministic with our shift generation and tile iteration for margin=0: single tile.
			require.ElementsMatch(t, tt.wantCenters, got)
		})
	}
}